1. Field of the Invention
The present invention relates to a power supply device, and more particularly to an on-vehicle power supply device.
2. Description of Related Art
In recent years, technological industries are developed rapidly, and electronic technologies are integrated and applied extensively in many different fields to gain competitive edges and values. As to the automobile industry, more and more automobile electronics are applied and integrated into cars each year. For example, LED related products, multimedia A/V products, monitoring devices and global positioning systems (GPS) are installed in cars. Of course, many technologies also modify their designs to support more on-vehicle electronic products, and thus this business opportunity obviously becomes one of the key factors for the development of electronics in the future.
To integrate or support the electronic peripheral devices, designers and manufacturers need to solve the issue of the on-vehicle power supply first. Since users generally obtain electric power directly from the DC power of a car battery through a cigarette lighter in a car or the AC power output (with a voltage of 110V/220V similar to that of the utility power) obtained through converting the power of the car battery by the so-called car inverter. If a user intends to use a DC electronic peripheral device through the car inverter in a car, the user needs to use an AC/DC adapter originally bundled with the DC electronic peripheral device, but such application is inconvenient and occupies space in the car.
In addition, the main issue of the prior art resides on that users cannot obtain a power supply continuously, since the car battery supplies electric power to users only when the car engine is turned on. If the car engine is turned off, the users no longer can obtain the electric power of car battery from the cigarette lighter or converted by the car inverter. As a result, the users cannot continue using the electronic peripheral device.
Finding a feasible solution for the on-vehicle power supply and providing users different voltages by a multipurpose, safe and continuous method demand further researches and improvements.